We investigate the optimal strategy over a finite time horizon for a portfolio of stock and bond and a derivative in an multiplicative Markovian market model with transaction costs (friction). The optimization problem is solved by a Hamilton-Bellman-Jacobi equation, which by the verification theorem has well-behaved solutions if certain conditions on a potential are satisfied. In the case at ha...

For control applications involving small displacements and velocities, friction modeling and compensation can be very important. In particular, the phenomena of stiction and presliding displacement (motion during sticking) can play pivotal roles. In this paper, it is shown that existing single-state-variable friction models possess either stiction or presliding displacement. Next, those models ...

We calculate the friction force acting on a hard cylinder or spherical ball rolling on a flat surface of a viscoelastic solid. The rolling-friction coefficient depends non-linearly on the normal load and the rolling velocity. For a cylinder rolling on a viscoelastic solid characterized by a single relaxation time Hunter has obtained an exact result for the rolling friction, and our result is in...

Simulating frictional contact between objects with complex geometry is important for 6-DoF haptic rendering applications. For example, friction determines whether components can be navigated past narrow clearances in virtual assembly. State-of-the-art haptic rendering of frictional contact either augments penalty contact with frictional penalty springs, which do not prevent sliding and cannot r...

We present a new method of neural friction compensa tion in manipulator control especially during dynamic tasks with de ned contact to external environment Such manipulator movements involve internal joint friction and external friction between tool and environment The suggested method compensates friction caused dis turbances by means of neural networks Based on a minimal friction model Lyapun...

Recent research on friction in robot joints and transmission systems has considered meshing friction a position-dependent friction component. However, in this paper we show experimental evidence that meshing friction depends highly on joint speed. We identify the meshing friction in the gearboxes of a robotic leg, and we propose a new mathematical model that considers the rate dependency of mes...

The long-time/large-scale, small-friction asymptotic for the one dimensional Langevin equation with a periodic potential is studied in this paper. It is shown that the FreidlinWentzell and central limit theorem (homogenization) limits commute. We prove that, in the combined small friction, long-time/large-scale limit the particle position converges weakly to a Brownian motion with a singular di...

OBJECTIVE The aim of this article was to assess how intraoral biodegradation influenced the surface characteristics and friction levels of metallic brackets used during 12 and 24 months of orthodontic treatment and also to compare the static friction generated in these brackets with four different methods of the ligation of orthodontic wires. MATERIAL AND METHODS Seventy premolar brackets as ...

N. Ratković, Faculty of Engineering, University of Kragujevac, Kragujevac, Serbia. R. Nikolić, Faculty of Civil Engineering, University of Žilina, Žilina, Slovakia. I. Samardžić, University of Osijek, Mechanical Engineering Faculty in Slavonski Brod, Croatia. Fundamental principles of friction welding of dissimilar steels (high speed and tempering steel) from the aspect of metallurgical and che...

Mobile robotic manipulators can augment the strength and dexterity of human operators in unstructured environments. Here, the control system for a six degree-of-freedom heavy-lift mobile manipulator for lifting and inserting payloads on the deck of a ship is described. The robotic hardware and the application present several control challenges, including structural resonances, high joint fricti...